Stage cementing tool

ABSTRACT

A stage cementing tool for use in cementing a casing in the well is disclosed. The stage cementing tool includes a housing with a mechanically set packer to seal against the well. A hydraulically actuated opening sleeve will move in the housing to uncover flow ports in the housing, and allow flow therethrough into the well.

BACKGROUND

When wellbores are prepared for oil and gas production it is common to cement casing in the wellbore. Oftentimes it is desirable to cement the casing in the wellbore in separate stages, typically beginning at the bottom of the well and working upwardly.

The process may be achieved by placing cementing tools, such as for example valved ports in the casing or between casing joints at one or more locations in the wellbore. Cement may be flowed through the bottom of the casing, up the annulus to the lowest cementing tool. Flow to the bottom of the casing can then be shut off. The cementing tool is opened and cement may be flowed through the cementing tool up the annulus to the next upper cementing tool. The process may be repeated until all stages of the well are cemented. Cementing tools are shown for example in U.S. Pat. Nos. 5,038,862 and 5,314,015. The '015 patent discloses a stage cementing tool which utilizes an inflatable packer apparatus. While there are cementing tools available, there is a continuing need for further development of efficient cementing tools and particularly efficient and effective stage cementing tools.

SUMMARY

A cementing tool with a housing defining a longitudinal flow passage therethrough is disclosed. The housing has at least one flow port and preferably has a plurality of flow ports disposed in a wall thereof. A mechanically set packer is connected to the housing for sealing against a well. The cementing tool may be used in a cased or uncased wellbore and thus the mechanically set packer will set and seal against a casing and/or an open wellbore in a well. The cementing tool has a hydraulically actuated opening sleeve in the housing that is movable from a closed position that covers the at least one flow port to an open position wherein the at least one flow port is uncovered to communicate the longitudinal flow passage with the well through the flow port. The hydraulically actuated opening sleeve is hydraulically actuated in that simply the application of pressure will open the opening sleeve and there are no additional plugs or setting tools used or needed to apply any moving force to the opening sleeve.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 schematically shows a stage cementing tool in a well.

FIG. 2 is a cross-section view of the stage cementing tool in a run-in position.

FIG. 3 shows the stage cementing tool of FIG. 2 with a packer moved to the set position.

FIG. 4 shows the tool of FIG. 2 with the stage cementing sleeve moved to an open position to uncover flow ports.

FIG. 5 shows the tool of FIG. 2 with the operating sleeve and closing sleeve moved to cover the flow ports.

DESCRIPTION OF A PREFERRED EMBODIMENT

FIG. 1 schematically shows a well 10 drilled for the production of hydrocarbons. Well 10 comprises wellbore 15 and casing 20 cemented therein. An annulus 25 is defined between casing 20 and wellbore 15. A stage cementing collar 30 may be lowered into the well on a casing 32. An annulus 34 is defined between wellbore 15 and casing 32. Casing 32 has an upper portion 36 and a lower portion 38. The lower portion 38 of casing 32 is below stage cementing collar 30 and upper portion 36 is above stage cementing collar 30.

Referring now to FIG. 2, stage cementing collar 30 includes housing 40 with upper end 42 and lower end 44, and is adapted to be connected in casing 32. Housing 40 has an outer or external surface 46 and an inner surface 48. Housing 40 defines a flow passage 50 from the upper to the lower end thereof to allow the passage of fluids therethrough. A packer assembly 52 is connected to housing 40 and may be threadedly connected at threads 54 to housing 40. Packer assembly 52 may be for example a mechanically set packer. Packer assembly 52 may comprise a packer sub or housing 56 with threads 58 for connecting into casing 32. Packer sub 56 has a packer element or a plurality of expandable packer elements 60 mounted thereto and disposed about housing 40. Expandable packer element 60 has upper end 62 and lower end 64. A movable upper end ring 66 is disposed about housing 40 and engages upper end 62 of packer element 60.

A packer setting sleeve 68 is slidably disposed in housing 40 and has inner surface 70. A packer setting sleeve seat 72 is attached to or alternatively may be formed with packer setting sleeve 68 and extends radially inwardly from a diameter 74 defined by inner surface 70. A plurality of connectors 76 extend from packer setting sleeve 68 through packer setting slots 78 which are defined in housing 40 and into upper end ring 66 so that packer setting sleeve 68 is connected to upper end ring 66. Connectors 76 are movable in packer setting slots 78 which have upper end 80 and lower end 82. Packer setting sleeve 68 sealingly engages housing 40 and may have O-rings 84 positioned above upper end 80 of packer setting slot 78 and O-rings 86 positioned below lower end 82 of packer setting slots 78 to sealingly engage housing 40.

A second stage opening sleeve 90, which may be referred to as a stage cementing sleeve 90, which in the embodiment shown is a hydraulically actuated opening sleeve 90, is positioned in housing 40 above packer setting sleeve 68. FIG. 2 shows the stage cementing collar 30 in the run-in position in which second stage opening sleeve 90 covers flow ports 92 defined in housing 40. Flow ports 92 may be referred to as circulating ports 92. As will be explained in more detail hereinbelow, when second stage opening sleeve 90 moves in housing 40, flow ports 92 are uncovered so that they are communicated with flow passage 50 to allow fluid flow therethrough into annulus 34. Second stage opening sleeve 90 has upper end 94 and lower end 96. Second stage opening sleeve 90 has first or upper portion 98 which comprises a first outer diameter 100. First portion 98 sealingly engages housing 40 on the inner surface 48 thereof, and may have O-ring 102, which may be referred to as upper seal 102, disposed thereon to sealingly engage housing 40. Second or lower portion 104 of second stage opening sleeve 90 has an outer diameter 106 smaller in magnitude than diameter 100 and has an O-ring 108, which may be referred to as lower seal 108, disposed therein. Second portion 104 sealingly engages a sealing or anchor ring 110 that is attached in housing 40. Second stage opening sleeve 90 is detachably connected in housing 40 with a plurality of shear pins 112. Second stage opening sleeve 90 has inner surface 114 that defines a bore therethrough to allow the passage of fluids therethrough.

An operating sleeve 120 is slidably and sealably disposed in housing 40. Operating sleeve 120 has upper end 122 and lower end 124 which, prior to movement of sleeve 90, abuts the upper end of second stage cementing sleeve 90. Operating sleeve 120 defines an open bore 126. A plurality of shear pins 128 detachably connect operating sleeve 120 to housing 40. A plurality of connectors 130 may be threadedly attached or otherwise attached to operating sleeve 120 and will extend therefrom through operating slots 132 in housing 40. Operating slots 132 have an upper end 134 and lower end 136. Operating sleeve 120 has an operating seat 138 at or near upper end 122 thereof.

A closing sleeve 140 is slidably disposed about housing 40. Connectors 130 extend into closing sleeve 140 to connect operating sleeve 120 and closing sleeve 140. A seal 142 is disposed in a groove in closing sleeve 140 above upper end 134 of operating slot 132. A seal 144 which may be referred to as a lower seal is disposed in a groove in closing sleeve 140 below lower end 136 of operating slots 132.

The cementing tool thus includes packer assembly 52 which is a mechanically set packer and hydraulically set second stage cementing sleeve 90. Referring now to FIG. 3, the stage cementing collar 30 is shown with an opening plug or cementing plug 150 landed on packer setting sleeve seat 72. Hydraulic pressure has been increased to move packer setting sleeve 68 in a first direction, downwardly in the embodiment shown, causing packer element 60 to expand and engage the wall of wellbore 15. While stage cementing collar 30 is shown in uncased wellbore 15, it is understood that it can be used in a cased wellbore as well. When packer setting sleeve 68 moves downwardly, upper end ring 66 moves downwardly, which causes the expansion of packer element 60. Cementing plug 150 may be a freefall plug which will be displaced into casing 32 after an initial volume of cement is pumped into the casing which will pass through the lower end thereof and will fill the annulus with cement up to or beyond the location of the stage cementing tool 30. Cementing plug 150 also may be of a type with wipers thereon. Packer setting sleeve 68 will completely cover packer setting slot 78 both in the run-in position shown in FIG. 2 and in the set position shown in FIG. 3, thus preventing communication and any pressure loss therethrough.

Once the packer 52 is in the set position as shown in FIG. 3, hydraulic pressure is increased and second stage cementing sleeve 90 is moved to the open position as shown in FIG. 4 which uncovers circulating ports 92. Increased pressure will cause shear pins 112 to break so that second stage opening sleeve 90 moves downwardly to uncover the circulating ports 92. The differential area between first and second portions 98 and 104 and more specifically between the sealing diameter of upper seal 102 and lower seal 108 will apply hydraulic pressure such that shear pins 112 will break allowing stage cementing sleeve 90 to move. Thus, no plugs, balls or other devices are needed to move stage cementing sleeve 90, which will move solely upon the application of increased pressure. Circulating ports 92 are thus communicated with and intersect flow passage 50 so that cement may be communicated therethrough into annulus 34. A volume of cement is flowed through circulating ports 92 and after the desired volume of cement is flowed through circulating ports 92, a cementing plug 152 as shown in FIG. 5, may be pumped in at the end trailing edge of the cement until it engages operating seat 138 on operating sleeve 120. An increase in pressure will cause shear pins 128 to break so that operating sleeve 120 moves downwardly and connected closing sleeve 140 likewise moves downwardly to cover circulation ports 92. This position is shown in FIG. 5. Once the process is complete, the sleeves and/or cement in the casing can be drilled out and stimulation and production operations may be carried out.

Instead of waiting on the first stage cement to set, as is normally required, second stage cementing can take place immediately after packer 52 is set so that packer element 60 seals against the well. Once packer 52 is set, it will hold the hydrostatic pressure from the second stage slurry which will be placed above the set packer element 60.

Thus, it is seen that the apparatus and methods of the present invention readily achieve the ends and advantages mentioned as well as those inherent therein. While certain preferred embodiments of the invention have been illustrated and described for purposes of the present disclosure, numerous changes in the arrangement and construction of parts and steps may be made by those skilled in the art, which changes are encompassed within the scope and spirit of the present invention as defined by the appended claims. 

1. A cementing tool for use in a well comprising: a housing defining a longitudinal flow passage therethrough, and having at least one flow port disposed in a wall thereof; a mechanically set packer connected to the housing for sealing against a well; and a hydraulically actuated opening sleeve disposed in the housing, the opening sleeve being movable from a closed position covering the at least one flow port to an open position wherein the at least one flow port is uncovered and communicates the longitudinal flow passage with the well.
 2. The cementing tool of claim 1, the mechanically set packer comprising: a packer sub connected to the housing; a radially expandable packer element supported by the packer sub and disposed about the housing; and a packer ring slidable on the housing and positioned so that movement of the packer ring in a first direction will cause the packer element to move to a set position wherein the packer element sealingly engages the well.
 3. The tool of claim 2 further comprising a packer setting sleeve disposed in the housing and connected to the movable packer ring, wherein movement of the setting sleeve in the first direction moves the packer ring in the first direction.
 4. The tool of claim 3, the housing having packer setting slots in the wall thereof, the setting sleeve being connected to the packer ring with connectors extending through the packer setting slots and movable therein.
 5. The tool of claim 4 wherein the packer setting sleeve completely covers the setting packer slots in the set and unset positions of the packer.
 6. The tool of claim 3 wherein the packer setting sleeve includes a seat for receiving a setting plug and wherein the setting sleeve will move the packer ring to expand the packer element to the set position when the setting plug is engaged with the seat and pressure in the longitudinal flow passage is increased.
 7. The cementing tool of claim 1, wherein the hydraulic setting sleeve has an upper portion with a first outer diameter and a lower portion with a second outer diameter smaller in magnitude than the first outer diameter.
 8. The cementing tool of claim 7, further comprising a closing sleeve disposed about the housing and detachably connected thereto for covering the flow ports after the opening sleeve has moved to the open position and cement has been flowed through the flow ports.
 9. A cementing tool for use in a well comprising: a housing defining a flow passage; a packer element disposed about the housing and movable from an unset to a set position wherein the packer element engages the well; a hydraulically actuated opening sleeve movable from a closed to an open position, wherein in the open position the opening sleeve uncovers circulating ports in the housing for communicating cement from the flow passage into the well.
 10. The cementing tool of claim 9 further comprising a closing sleeve disposed about the housing and positioned above the opening sleeve for covering the circulating ports after cement has been communicated therethrough.
 11. The cementing tool of claim 10, further comprising an operating sleeve detachably connected in the housing, the closing sleeve being connected to and movable with the operating sleeve.
 12. The cementing tool of claim 11 further comprising a packer setting sleeve disposed in the housing, wherein the packer setting sleeve is adapted to move the packer element to the set position.
 13. The cementing tool of claim 12 wherein a first plug is displaced into the tool to move the packer setting sleeve and a second plug is displaced in the tool to move the operating sleeve.
 14. The cementing tool of claim 9 the hydraulically actuated opening sleeve comprising an upper portion having a first outer diameter, and a lower portion with a second, smaller diameter, wherein the opening sleeve is detachably connected to the housing in the closed position in which the opening sleeve prevents communication through the circulating ports.
 15. A cementing tool for use in a wellbore comprising: a housing, the housing and the wellbore defining an annulus therebetween; a packer element disposed about the housing for engaging the wellbore; a packer setting sleeve for expanding the packer element to engage the wellbore; an opening sleeve movable relative to the housing and the packer setting sleeve, wherein in a closed position the opening sleeve blocks communication into the annulus and in the open position permits flow into the annulus through circulation ports in the housing.
 16. The cementing tool of claim 15 wherein the opening sleeve is disposed in the housing and movable solely upon the application of hydraulic pressure in the housing.
 17. The cementing tool of claim 15, further comprising a packer end ring at the upper end of the packer element wherein the packer setting sleeve is connected to the packer end ring.
 18. The cementing tool of claim 17, wherein the housing has slots defined therein, and where connectors extend through the slots to connect the packer setting sleeve to the packer end ring, the packer setting sleeve completely covering the slots. 